Tele-writing system, for each other changing image displayed on another terminal, having function of identifying document to be processed in tele-writing operation

ABSTRACT

An identifier-adding unit adds an identifier to sending tele-writing information to be sent from the first tele-wiring system to a second tele-writing system via telecommunication. The identifier is used to identify a document to be processed as a result of a tele-writing operation being specified. This causes a second picture displayed on the second tele-wiring system to be affected, if appropriate, according to the sending tele-writing information. The information corresponds to a first tele-writing operation for affecting a first picture displayed on the first tele-writing system. A document identifying unit identifies, using an identifier added to received tele-writing information sent from the second tele-writing system to the first tele-writing system, a corresponding document to be processed as a result of the tele-writing operation being specified.

This is a Continuation of application Ser. No. 08/185,399 filed on Jan.24, 1994 now U.S. Pat. No. 5,521,335.

BACKGROUND OF THE INVENTION

The present invention relates to a tele-writing terminal device by whichdrawing information, such as that concerning texts and/or figures, aswell as information concerning voice is transferred through mutualcommunications via a communication network such as an Integrated ServiceDigital Network (ISDN hereinafter), a telephone communication network,or a private line network. The present invention in particular relatesto a tele-writing terminal device, a conference system being realized byinterconnecting a plurality of the tele-writing terminal devices.

An example of a conference system realized by interconnecting aplurality of a tele-writing terminal devices will now be described. Aplurality of documents may be simultaneously displayed commonly on thedisplay devices associated with respective ones of the plurality oftele-writing terminal devices. In such a case, if each conference memberarbitrarily and randomly specifies adding/deleting operations so as toaffect the displayed documents, the displayed documents are affected ina disorderly fashion affected, resulting in confusion in the conference.

In order to prevent such confusion, the following system may be used: Aconcept of control right such as addition/deletion right is used so thatonly a tele-writing terminal device, among those holding the conference,which currently has the control right can be allowed to perform anaddition/deletion operation so as to affect the common picturecomprising the displayed documents. In this specification, the termaddition operation means an operation, normally performed by an operatoron a relevant terminal device which operation is intended to affect apicture, representing figures and/or texts, so that a certain element,comprising a line, dot, etc. for example, is added to the existingpicture. Further, the term deletion operation means an operation,performance of which operation is intended to affect a picture,representing figures and/or texts, so that a certain element, comprisinga line, dot, etc. for example, is removed from the existing picture.Further, the term alteration operation means an operation, performanceof which operation is intended to affect a picture, representing figuresand/or texts, so that the picture is magnified in size or is reduced insize or is replaced by another one stored in a predetermined storage,for example.

Another system as follows using the above proposed system may also beused: In the other system, information concerning performance of anaddition/deletion operation to affect the common picture, occurring inthe tele-writing terminal device not having the control right, iseffectively used. That is, the addition/deletion operation informationis first sent to the tele-writing terminal device having the controlright, said tele-writing terminal device then determines for the sentinformation as follows: Said tele-writing terminal device determineswhether the sent information is valid so that the correspondingaddition/deletion operation is allowed to be performed so as to affectthe common picture or the sent information is invalid so as to beignored. Such a system is disclosed in Japanese Patent Laid-OpenApplication No. 3-150939, for example.

Certain difficulties/problems may arise in such a system as that of theformer example wherein only a conference member whose terminal has thecontrol right is allowed to perform the addition/deletion operation soas to affect the common picture. Such difficulties/problems may arise,for example, when hot debate occurs in the conference. Then, transfer ofthe control right to the terminal of a conference member who wishes toargue by affecting the common picture is problematic.

Another problem may occur in a system such as that of the latter examplewherein a conference member whose terminal has the control right mayallow/reject an addition/deletion operation, to be performed on thecommon picture, requested by another member whose terminal thus does nothave the control right. In that case, actually, the following system maybe employed in practice: First, in the terminal not having the controlright, the relevant addition/deletion operation is specified by theoperator temporarily so as to affect the picture displayed on theterminal's screen. Information concerning the relevant addition/deletionoperation is sent to the terminal having the control right. Then, in theterminal possessing the control right, based on the received relevantinformation, the same addition/deletion operation is specified by theoperator so as to temporarily affect the picture displayed on theterminal's screen. Then, the conference member whose terminal has thecontrol right determines whether the relevant addition/deletion will beallowed or rejected. In the case of rejection, the temporary effect ofthe relevant addition/deletion operation is canceled from the picturedisplayed on the screen of the terminal possessing the control right.Simultaneously, information indicating the determination result ofrejection is sent to the terminal not possessing the control right.Then, at the terminal not possessing the control right, based on theresult of rejection, the temporary effect of the relevantaddition/deletion operation is canceled also from the picture displayedon the screen of the terminal not possessing the control right. Asdescribed above, the actual process comprises a rather complicatedcontrol process.

Further, in the above system, the following difficulties/problems mayarise: It may occur that respective addition/deletion operations aresimultaneously specified by the corresponding operators on a pluralityof terminals, each not having the control right so that the commonpicture is affected accordingly. In such a case, the conference memberwhose terminal has the control right must decide between plurality ofrequests.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a tele-writing terminaldevice which enables proper selection of a document from among aplurality of documents which may constitute the common picture,performance of the relevant addition/deletion operation affecting theselected document.

Another object of the present invention is to provide a tele-writingterminal device which enables unrestricted and straightward/simpleperformance of addition/deletion operations so as to affect the commonpicture without carrying out either transfer of the control right orcomplex operations associated with the control right which causeoperation performance to be degraded.

To achieve the above objects of the present invention, a tele-writingsystem according to the present invention comprises:

identifier-adding means for adding an identifier to sending tele-writinginformation to be sent from the first tele-writing system to a secondtele-writing system by telecommunication, said identifier being used toidentify a document to be affected by a tele-writing operation, in whicha second picture displayed on said second tele-writing system isaffected, if appropriate, according to said sending tele-writinginformation, which corresponds to a first tele-writing operation foraffecting a first picture displayed on said first tele-writing system;and

document identifying means for identifying, using an identifier added toreceived tele-writing information sent from said second tele-writingsystem to said first tele-writing system, a document to be affected bysaid tele-writing operation.

The above system may further comprise:

page-number adding means for adding a page number to said sendingtele-writing information, said page number concerning a page of adocument, which page is to be affected by said tele-writing operation;and

page identifying means for identifying, using a page number added tosaid received tele-writing information, a corresponding page to beaffected by said tele-writing operation.

As a result, identification of a page of the document as well asidentification of the document, on which page the relevantaddition/deletion is to be performed, can be ensured.

The above system may further comprise:

terminal-number adding means for adding a terminal number to saidsending tele-writing information, said terminal number concerning saidtele-writing system; and

terminal identifying means for identifying, using a terminal numberadded to said received tele-writing information, said secondtele-writing system.

As a result, easy identification of the terminal which sends therelevant information is enabled.

The above system may further comprise:

sequential-number adding means for adding a sequential number to saidsending tele-writing information, said sequential number being eitherincremented or decremented, as is appropriate, depending on which kindof tele-writing operation is specified on said first tele-writingsystem;

comparing means for comparing said sequential number with a sequentialnumber added to said received tele-writing information;

sequential-number updating means for either incrementing or decrementingthe sequential number as is appropriate according to the result of thecomparison performed by said comparing means;

difference detecting means for detecting a difference between said firstand second pictures based on said result of said comparison performed bysaid comparing means; and

correcting means for correcting said difference detected by saiddifference detecting means.

Further, said correcting means may comprise re-affecting means forcausing operations once performed on said first picture to take effectagain according to said first tele-writing operation.

As a result, the capability of making pictures displayed on respectiveterminals screens identical is provided.

The above system may comprise examining means for examining contents ofsaid received tele-writing information along and also examining thecombination of said received and sending tele-writing information so asto determine how said first tele-writing system processes said receivedand sending tele-writing information. As a result, the receivedtele-writing information can be processed in the first tele-writingsystem properly. Further, the result of the received tele-writinginformation may be displayed on the first tele-writing system's screenso that the operator may easily confirm the contents of the receivedtele-writing information.

The above system may further comprise invalidating means forinvalidating said receiving tele-writing information if appropriateaccording to the result of the examination carried out by saiddetermining means. As a result, improvement in the operation performancemay be realized.

The above system may further comprise returning means for returning saidreceiving tele-writing information to said second tele-writing system ifappropriate according to the result of the examination carried out bysaid determining means. As a result, improvement in the operationperformance may be realized because the displayed pictures can be keptconsistent with one another.

The above system may further comprise editing means for editing saidreceiving tele-writing information if and as appropriate according tothe result of the examination carried out by said determining means. Asa result, improvement in the operation performance may be realizedbecause the operator associated with the second tele-writing system mayconfirm the result of the editing resulting form the examination.

The above system may further comprise designating means for designatingan appropriate action procedure for each command included in thetele-writing information, said action procedure concerning whether aone-way procedure or a return procedure is designated, wherein, in saidone-way procedure, the command is used for affecting said first pictureand then sent to said second tele-writing system and then used foraffecting said second picture; and in said return procedure, the commandis first sent to said second tele-writing system for the purpose ofaffecting said second picture and then sent back to said firsttele-writing system for the purpose of affecting said first picture.

Further, in the above system:

said one-way procedure is designated for the command indicating additionof contents to said first and second pictures;

said return procedure is designated for the command indicating deletionof contents from said first and second pictures; and

said return procedure is designated for the command indicatingpredetermined alteration of the displaying style of said first andsecond pictures or replacement of the contents of said first and secondpictures with other previously stored contents.

As a result, improvement in the operation performance may be realizedbecause the tele-writing process may be carried out appropriately toeach command.

Other objects and further features of the present invention will becomemore apparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG.1 shows a block diagram of a tele-writing terminal device in a firstembodiment of a tele-writing system according to the present invention;

FIG. 2 shows a block diagram of a conference system comprisingtele-writing terminal devices as shown in FIG. 1;

FIG. 3 shows an example of a format for tele-writing information, to betransferred between respective tele-writing terminal devices, in thefirst embodiment of the tele-writing system according to the presentinvention;

FIG. 4 shows an operation flow at the beginning of a conference held inthe conference system of FIG. 2 in the first embodiment of thetele-writing system according to the present invention;

FIG. 5 shows an operation flow for document identification and displayupdating in the first embodiment of the tele-writing system according tothe present invention;

FIG. 6 shows an example of a display on a display unit in the firstembodiment of the tele-writing system according to the presentinvention;

FIGS. 7A and 7B show respective displayed documents each comprisingpluralities of pages, in the first embodiment of the tele-writing systemaccording to the present invention;

FIG. 8 shows an example of the tele-writing information in the firstembodiment of the tele-writing system according to the presentinvention;

FIG. 9 shows an example of a sequential-number updating operationsequence in which the tele-writing information is transferred betweenthe terminals in the first embodiment of the tele-writing systemaccording to the present invention;

FIG. 10 illustrates the undesirable difference generation processgenerating differences in pictures displayed on screens of respectiveterminals in the first embodiment of the tele-writing system accordingto the present invention;

FIG. 11 shows an example of a signal transfer operation sequence ofsteps S₅₀ -S₅₃ in a second embodiment of the tele-writing systemaccording to the present invention;

FIG. 12 shows an operation flow in which an addition operation isspecified by the operator in the second embodiment of the tele-writingsystem according to the present invention;

FIG. 13 shows a determination table for determining a task to be carriedout when the tele-writing information is received in the secondembodiment of the tele-writing system according to the presentinvention;

FIGS. 14A, 14B and 14C show operation flows of TASKs 1-3 respectively inthe second embodiment of the tele-writing system according to thepresent invention;

FIG. 15 shows an example of a signal transfer sequence of steps S₆₁ -S₆₅in the second embodiment of the tele-writing system according to thepresent invention;

FIG. 16 shows variation of pictures displayed on the terminals whereperformance of a deletion operation takes effect in response toreceiving a returned command in the second embodiment of thetele-writing system according to the present invention;

FIG. 17 shows variation of the pictures in the same case as in FIG. 16but resulting from improvement in operation procedure being performed onthe process of FIG. 16 in the second embodiment of the tele-writingsystem according to the present invention;

FIGS. 18A and 18B show operation flows of TASKs 4 and 5 respectively inthe second embodiment of the tele-writing system according to thepresent invention;

FIG. 19 shows an operation flow of TASK 6 in the second embodiment ofthe tele-writing system according to the present invention; and

FIG. 20 shows an example of a signal transfer sequence of a step S₇₁ inthe second embodiment of the tele-writing system according to thepresent invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described withreference to drawings.

FIRST EMBODIMENT!

A tele-writing terminal device in a first embodiment of the tele-writingsystem according to the present invention will now be described withreference to FIGS. 1-10. First, a construction will be described withreference to FIG. 1. The tele-writing terminal device 20 of FIG. 1comprises a line control unit 1, a drawing coder and decoder (coder anddecoder will be referred to as CODEC, hereinafter) unit 2, avoice-input/output control unit 3, a voice input/output unit 4, astorage unit 5, an overall control unit 6, an input/output control unit7, a drawing input unit 8, a control-information input unit 9 and adisplay unit 10. This tele-writing terminal device 20 has a capabilityof communication such that the device 20 can communicate voiceinformation and drawing information with one or a plurality oftele-writing terminal devices.

The circuit control unit 1 acts as an interface between the tele-writingterminal device 20 and the communication line 11. The drawing CODEC unit2 performs coding and decoding of drawing information. The voiceinput/output control unit 3 controls input and output of voiceinformation. The unit 3 includes a voice CODEC unit foranalog-to-digital converting in a case where the device 20 is connectedto ISDN. The voice input/output unit 4 performs input and output ofvoice information and may comprise devices such as a telephone handset,a microphone, and speaker, for example.

The overall control unit 6 performs overall control of the tele-writingterminal device 20. The input/output unit 7 controls input and output ofinformation such as drawing information and/or control information. Thedrawing input unit 8 inputs drawing information. The control-informationinput unit 9 inputs control information. The display unit 10 displaysdrawing information and/or control information for example and displaysa common picture comprising drawing information resulting from themutual communication. The communication line 11 comprises ISDN, atelephone line or a private line.

A conference system comprising tele-writing terminal devices includingthe above described tele-writing terminal device 20 (may be referred tosimply as a terminal A) will now be described with reference to FIG. 2.Each of the other tele-writing terminal devices 21, 22 and 23 (may bereferred to simply as a terminals B, D and E respectively as shown inFIG. 2, hereinafter) comprises a construction similar to that of thetele-writing terminal device 20. These terminals A-D are located inrespective regions separate from each other and connected with eachother as shown in FIG. 2 through a network or a conference controller 30via the line 11. There may be another example where a plurality ofterminals are located in the same region. In such a case, the terminalsA and B are located in a region and the terminals C and D are located inanother region.

There, as described above, the tele-writing terminal device 20 has thefollowing capability: The device 20 is connected with one or a pluralityof remote terminal devices via a predetermined line; the device 20 sendsand/or receives tele-writing information including drawing information;the device 20 displays a picture common to one displayed on the remoteterminal device; and performance of an addition/deletion operation mayaffect the common picture, which operation is specified by thecorresponding operator on either the device 20 itself or the remoteterminal device. The overall control unit 6 thereof comprises thefollowing means: document-identifier adding means; documentidentification means; page-number adding means; page identificationmeans; terminal-number adding means; terminal identification means;sequential-number adding means; comparing means; sequential-numberupdating means; display-difference detecting means; and re-affectingmeans.

The overall control unit 6, now acting as the document-identifier addingmeans, adds, to the above tele-writing information, a documentidentifier for identifying a document, which document performance of theabove addition/deletion operation will affect. This addition is carriedout before the above tele-writing information is sent out. The overallcontrol unit 6, now acting as the document identification means,identifies the document which the above addition/deletion operation willaffect. This identification is carried out, when the tele-writinginformation is received, using the identifier added to the receivedtele-writing information.

The overall control unit 6, now acting as the page-number adding means,adds, to the above tele-writing information, a document page number foridentifying a page of the document, which page the aboveaddition/deletion operation will affect. This addition is carried outbefore the above tele-writing information is sent out. The overallcontrol unit 6, now acting as the page identifying means, identifies thepage of the document, which page the above addition/deletion operationwill affect. This identification is carried out, when the tele-writinginformation is received, using the document page number added to thereceived tele-writing information.

The overall control unit 6, now acting as the terminal-number addingmeans, adds, to the above tele-writing information, a terminal numberwhich has been previously set for the device 20 itself. The overallcontrol unit 6, now acting as the terminal identifying means, identifiesthe terminal, on which terminal the relevant addition/deletion operationis specified by the operator. This identification is carried out, whenthe tele-writing information is received, using the correspondingterminal number added to the received tele-writing information.

The overall control unit 6, now acting as the sequential-number addingmeans, adds a sequential number on the tele-writing information beforethis tele-writing information is sent out. The sequential number is anumber previously set on the terminal 20 itself (local terminal,hereinafter) and is altered (or updated) as appropriate to whichoperation among a plurality of predetermined addition/deletionoperations has been specified by the operator. The overall control unit6, now acting as the comparing means, compares between the sequentialnumber added to the received tele-writing information and the sequentialnumber set on the local terminal. This comparison is carried out whenthe received tele-writing is received. The overall control unit 6, nowacting as the sequential-number updating means, updates (or alters) thelocally set sequential number as appropriate to the result of the abovecomparison carried out by the comparing means. The overall control unit6, now acting as the display-difference detecting means, detects, basedon the result of the comparison, a difference between the commonpictures displayed on the local terminal and the remote terminal. Theoverall control unit 6, now acting as the re-affecting means, causes theperformance of the addition/deletion operation to take effect again,this affecting by the addition/deletion operation having been once madebefore the difference in the common pictures is thus detected. Thisre-affecting is carried out if the difference in the common pictures isdetected by the display-difference detecting means.

As shown in FIG. 3, a local terminal number, a document identifier, apage number and a sequential number are added to the tele-writinginformation.

Operations carried out in the tele-writing terminal device 20 in thefirst embodiment of the tele-writing system according to the presentinvention will now be described with reference to FIGS. 4-10.

First, in step S₁ (the term step will be omitted, hereinafter),telephone numbers of the remote terminal devices associated with aplurality of conference members who will attend the conference areinput. The input telephone numbers are, via the input/output controlunit 7, sent to the line control unit 1. In S₂, calling is performed tothe terminal device 21. The above operations are managed/controlled bythe overall control unit 6. The unit 6 subsequently sends terminalnumbers which will be used by the respective remote terminal devices inS₃. The reason for this transmission is as follows: The generation, bythe calling side terminal, of the terminal numbers for all of the remoteterminal devices prevents terminal numbers from being duplicated. In S₄-S₇, the operations similar to those in S₂ and S₃ are performed but onthe remote terminal devices 22 and 23 respectively.

Next, an operation flow when the drawing information is received will bedescribed with reference to FIG. 5.

In S₈, the tele-writing information is received via the line controlunit 1. This tele-writing information has the format shown in FIG. 3 forexample. According to this format, in S₉, the document identifier andpage number are extracted from the received tele-writing information.Using this extracted information, the document and page thereof to beaffected by performance of an addition/deletion operation, areidentified, that is, a drawing area is determined.

In S₁₀, if the determined drawing area is being displayed as a commonpicture, updating of the common picture is executed as follows in S₁₁ :Using drawing information such as that concerning drawing line type anddrawing position, drawing contents are derived; and the common pictureis updated using the derived drawing contents. On the other hand, if thedetermined drawing area is not being displayed as the common picture,information concerning the display contents in this drawing area is onlystored in the storage unit 5. Therefore, In S₁₂, using drawinginformation such as that concerning drawing line type and drawingposition, drawing contents are derived; and the display contents in thedrawing area stored in the storage unit 5 are updated using the deriveddrawing contents.

An example of the display of documents on the screen of the display unit10 will now be described with reference to FIG. 6. On the screen, asshown in FIG. 6, two different documents D₁ and D₂ are displayedsimultaneously. As shown in FIG. 7A, the first document D₁ comprises 4pages while the second document D₂ comprises 3 pages as shown in FIG.7B. On the screen of FIG. 6, the first page of the document D₁ and thethird page of the document D₂ are displayed. There, it is possible tomake performance of tele-writing operation affect the respectivedocument 1 (D₁) and document 2 (D₂). For example, the terminal Bperforms free drawing on the first page of the document 1. In this case,the corresponding tele-writing information comprises drawinginformation, shown in FIG. 8, having the local terminal number, documentidentifier and page number set accordingly.

The sequential number will now be described with reference to FIG. 9.There, the description will be made using an example of datacommunication between the terminals A and B.

Sequential numbers Na and Nb are stored in the terminals A and Brespectively and the stored sequential numbers become the terminals'local terminal sequential numbers respectively. When anaddition/deletion operation is specified by the operator, the sequentialnumber N, identical to the local-terminal sequential number, is added tothe relevant tele-writing information. In this tele-writing terminaldevice in the first embodiment, the local terminal number is updated inthe following manner: When a deletion operation is specified by theoperator on the terminal, 1 is added to the terminal's currentlocal-terminal sequential number; and When (the local-terminalsequential number)≦(received sequential number), the local-terminalsequential number becomes this received sequential number. Such aupdating procedure is only an example, and any other procedure may beused, such as adding 1 to the local-terminal sequential number when anaddition operation is specified by the operator.

First, in S₃₂, after an addition operation is specified by the operatoron the terminal A and the relevant addition-operation information issent to the terminal B, an addition operation is specified by theoperator on the terminal B and the relevant addition-operationinformation is sent to the terminal A. As a result of such processes asthose in S₃₂, no difference occurs between the resulting common documentpictures displayed on the respective terminals.

In S₃₃, addition operations are specified by the operators on theterminals A and B respectively and simultaneously and the relevantaddition-operation information packets are sent to the counterpartterminals respectively. As a result of processes such as those in S₃₃,no difference occurs between the resulting common document picturesdisplayed on the respective terminals because the specified operationscomprise addition operations respectively.

In S₃₄, after a deletion operation is specified by the operator on theterminal A and the relevant deletion-operation information is sent tothe terminal B, an addition operation is specified by the operator onthe terminal B and the relevant addition-operation information is sentto the terminal A. As a result of processes such as those in S₃₄, nodifference occurs between the resulting common document picturesdisplayed on the respective terminals.

In S₃₅, the following operations are simultaneously specified: adeletion operation is specified by the operator on the terminal A and anaddition operation is specified by the operator on the terminal B. Then,the relevant deletion-operation and addition-operation informationpackets are sent to the counter-part terminals respectively. As a resultof processes such as those in S₃₅, a difference may occur between theresulting common document pictures displayed on the respective terminalsA and B. That is, as shown in FIG. 10, at the top, both common picturesof the respective terminals A (left) and B (right) are identical. Then,a deletion operation G and an addition operation H are specified by theoperators on the terminals A and B simultaneously respectively. As aresult, the resulting common pictures become those shown at the centerof FIG. 10. Then, tele-writing information packets, indicating therelevant deletion operation G and addition operation H respectively, aresent to the counter-part terminals B and A respectively. In accordancewith the sent tele-writing information packets, the performance of theaddition operation H and the deletion operation G affect the pictures ofthe terminals A and B, respectively. As a result, the respectivepictures are different from one another as shown at the bottom of FIG.10 (the oblique line is continuous at the left picture and broken on theright). Such a difference may be detected as follows: Comparison isperformed between the local-terminal sequential number and the receivedsequential number in the terminal A; and as a result, if (thelocal-terminal sequential number)>(the received sequential number), adifference exists between the two resulting pictures. Then, after thedifference is detected, the following operation can remove such adifference so as to make both the pictures identical: In the terminal A,after the performance of the addition operation H affects the terminalA's picture, the deletion operation G, having once previously affectedthe picture before the specification of the addition operation H by theoperator, is again applied to the picture. As a result, the oblique lineof the picture shown at the bottom-left of FIG. 10 becomes broken,identically to the picture shown at the bottom-right of FIG. 10.

In S₃₆ of FIG. 9, deletion operations are simultaneously specified bythe operators on both the terminals A and B and the relevantdeletion-operation information packets are sent to the counter-partterminals B and A. As a result of processes such as those in S₃₆, nodifference occurs between the resulting common document picturesdisplayed on the respective terminals because the specified operationscomprise deletion operations respectively.

The above description of the tele-writing terminal device in the firstembodiment of the tele-writing system according to the present inventionwill now be summarized. The document identifier is added to thetele-writing information when the tele-writing information is sent. Bythis identifier, a document is identified in the remote terminal devicewhich has received the relevant tele-writing information, which documentperformance of an addition/deletion operation will affect. As a result,addition/deletion operations may be arbitrarily specified by theoperators on the respective tele-writing terminal devices even if aplurality of documents are simultaneously displayed as each of thecommon pictures. Further, transfer operation of control right among thetele-writing terminal devices may be eliminated so that operationperformance can be improved.

Further, not only information for identifying the relevant document butalso information for identifying the relevant page therein is added tothe relevant tele-writing information. Thus, the relevant page can beproperly identified.

Furthermore, even the terminal number of the terminal device which hassent the relevant tele-writing information is added to the tele-writinginformation. Therefore, the remote terminal device can properly identifythe information-source terminal device. As a result, an operation isenabled such as that the destination terminal device may requestresending of the relevant information to the information-source terminaldevice easily and properly, for example. Thus, operation performance canbe improved.

Further, the possibility can be eliminated that a difference occursbetween pictures displayed on the respective terminals due tosimultaneous specifications of addition and/or deletion operations bythe operators in the respective terminals. This elimination can beachieved as a result of detecting the occurrence of such a difference asdescribed above and in response to this, proper counter-measures asdescribed above can be taken so as to remove the difference.

(SECOND EMBODIMENT)

A tele-writing terminal device in a second embodiment of thetele-writing system according to the present invention may be applied tothe above tele-writing terminal device, described with reference toFIGS. 1-10, in the first embodiment of the tele-writing system accordingto the present invention. Here, characteristic parts of the tele-writingterminal device in the second embodiment will now be describedconcretely. First, in the above tele-writing terminal device in thefirst embodiment, as indicated by the determination in S₁₀ and theprocess in S₁₂ in FIG. 5, the affecting may be made as a result ofderiving the drawing contents of the relevant drawing area, even if therelevant drawing area is not displayed on the common picture. However,in this way, the storage unit has to bear a load proportional to thenumber of drawing areas and thus there may be a case of excessiveloading to be borne by the storage unit. In order to prevent such aproblem, in the tele-writing terminal device in the second embodiment,the following processes are performed: A currently displayed drawingarea is always made to be coincident between both the terminals. Thatis, even if displayed-page alteration, followed by correspondingdisplayed-drawing-area alteration, is performed on one terminal, thecorresponding displayed-drawing-area alteration is also performed on theother terminal simultaneously. As a result, communication data used inthe tele-writing process may comprise data concerning a drawing areabeing made to be coincident between the respective terminals.Accordingly, the need for the processes of S₁₀ and ₁₂ may be eliminated.The tele-writing terminal device in the second embodiment of thetele-writing system according to the present invention will now bedescribed with the corresponding drawings.

A signal-transfer sequence example according to the second embodiment ofthe present invention will now be described with reference to FIG. 11.S₅₀ comprises processes in which an addition operation is specified bythe operator. S₅₀ will now be described with reference to FIG. 12.First, the operator associated with the terminal A specifies an additionoperation on the terminal A and accordingly the terminal A determines inS₈₀ that a tele-writing operation exists. Because the relevanttele-writing operation comprises the addition operation in this case,the terminal A performs the following operations: The terminal A drawsthe corresponding object on the drawing area of the picture displayed onthe terminal A (thus the performance of the addition operation affectsthe drawing area), and edits transmission data correspondingly (S₈₈).Then, the terminal A sends the edited data to the terminal B via theline control unit (S₈₉). On the other hand, the terminal B determined inS₈₀ that no tele-writing operation exists because the operatorassociated with the terminal B does not performs any tele-writingoperation. Then, in S₈₁, the terminal B determines that receiving dataexists because the data sent from the terminal A in S₈₉ as mentionedabove is transferred to the terminal B. Then, the terminal B accepts thedata via the line control unit in S₈₂. Then, in S₈₃, the terminal Bdetermines the relevant drawing area using the document identifier andpage number indicated by the thus received data.

Then, the terminal B determines in S₈₄ using the terminal numberindicated by the received data whether or not a command indicated by thesame data comprises a returning command of a go-and-return type command.Go-and-return type command means a type of command which will betransmitted from a first terminal to a second terminal and then the samecommand is returned to the first terminal. Returning command means thecommand which are thus being returned. Because the relevant commandcomprises a one-way command in this case, the NO branch is selected inS₈₄. Then, in S₈₅, the terminal B determines an affecting task fromamong predetermined tasks shown in FIG. 13 and this determination isexecuted in accordance with the table shown in FIG. 13. In this case,the terminal B now acting as the local-terminal has no tele-writingoperation specified by its own operator (thus the top line of the tableis selected) and the data received from the terminal A now acting as theremote terminal comprises the addition-operation affecting command (thusthe leftmost row is selected). As a result, TASK-1 (located at thetop-left of the table of FIG. 13) is selected. Accordingly, the terminalB branches off into the selected TASK-1 in S₈₆ and executes TASK-1 inS₈₇. The process performed in TASK-1 will now be described withreference to FIG. 14A. In TASK-1, the terminal draws a certain object ona relevant drawing area so as to be affected in accordance with anaddition-operation affecting command indicated by received data in S₉₃.This operation will now be applied to the above described case where theterminal B has received the data indicating the addition-operationaffecting command from the terminal A. As a result, in TASK-1 in S₈₇ ofFIG. 12, the terminal B draws the above object on the relevant drawingarea displayed on its own picture so as to cause the area to be affectedby the addition-operation affecting command indicated by the datareceived from the terminal A. Thus, S₅₀ of FIG. 11 has been described.Further, S₅₁ of FIG. 11 is a step in a case where the terminal B sendsdata to the terminal A. Thus, S₅₁ is similar to S₅₀ but the roles playedby the terminals A and B are interchanged.

S₅₂ in FIG. 11 will now be described with reference to FIG. 12 and is asignal-transfer sequence example in which a deletion operation isspecified by the operator. First, the operator of the terminal Aspecifies a deletion-operation on the terminal A and thus the terminal Adetermines in S₈₀ that a tele-writing operation exists. Because therelevant existing tele-writing operation comprises the deletionoperation in this case, the terminal A only correspondingly editstransmission data in S₈₈. Thus, the performance of the deletionoperation does not take immediate effect but will take effect when theterminal A receives a returning command of the relevantdeletion-operation information in the second embodiment of thetele-writing system according to the present invention. The reason forsuch an operation procedure will be described below at the descriptionof S₆₂ of FIG. 15. Here, as mentioned above, the performance of thedeletion operation affects the drawing area when the terminal A receivesthe returning command of the deletion-operation information as will bedescribed now. The transmission data edited in S₈₈ as mentioned above issent to the terminal B via the line control unit in S₈₉. On the otherhand, the terminal B has no tele-writing operation specified by its ownoperator and determines in S₈₀ that no tele-writing operation exists.Then, because the data sent from the terminal A in S₈₉ as mentionedabove arrives at the terminal B, the terminal B determines in S₈₁ thatreceiving data exists. Then, the terminal B accepts the thus arriveddata via the line control unit in S₈₂. Then, the terminal B determinesin S₈₃ the drawing area, which area the relevant performance of thetele-writing operation indicated by the accepted data affects. Thisdetermination is executed using the document identifier and page numberindicated by the accepted data.

Then, the terminal B determines in S₈₄ using the terminal numberindicated by the received data whether or not a command indicated by thesame data comprises the returning command of the go-and-return typecommand such as described above. Because the relevant command comprisesa going command of the go-and-return type command in this case, thebranch of NO is selected in S₈₄. Then, in S₈₅, the terminal B determinesan affecting task from among predetermined tasks shown in FIG. 13 andthis determination is executed in accordance with the table shown inFIG. 13. In this case, the terminal B now acting as the local-terminalhas no tele-writing operation specified by its own operator (thus thetop line of the table is selected) and the data received from theterminal A now acting as the remote terminal comprises thedeletion-operation affecting command (thus the middle row is selected).As a result, TASK-2 (located at the top-middle of the table of FIG. 13)is selected. Accordingly, the terminal B branches off into the selectedTASK-2 in S₈₆ and executes TASK-2 in S₈₇. The process performed inTASK-2 will now be described with reference to FIG. 14B. In TASK-2, theterminal removes a specified element from a relevant drawing area so asto cause the area to be affected by a deletion-operation affectingcommand indicated by received data in S₉₄. Further, because all ofdeletion-operation affecting commands are go-and-return type commands,the terminal sends back the received data to the remote terminal as itis in S₉₅. These operations will now be applied to the above describedcase where the terminal B has received the data indicating thedeletion-operation affecting command from the terminal A. In TASK-2 inS₈₇ of FIG. 12, first, the terminal B removes, in S94, a specifiedelement from the relevant drawing area displayed in its own picture soas to cause the area to be affected by the deletion-operation affectingcommand indicated by the data received from the terminal A. Then, inS₉₅, the terminal B sends back the received data to the terminal A as itis. Then, the terminal A, after receiving the sent-back data, executesS₈₀, S₈₁ and S₈₂ in FIG. 12. Consequently, the terminal A, afteraccepting the sent-back data in S₈₂, then determines in S₈₃ the relevantdrawing area determined by the document identifier and page numberindicated by the thus accepted data. Then, the terminal A determines inS₈₄ that the accepted data comprises the returning data of thego-and-return type command. Then, in S₉₀, the terminal A performs therelevant deletion operation in accordance with the relevantdeletion-operation affecting command indicated by the sent-back andaccepted data. Thus, S₅₂ of FIG. 11 has been described.

S₅₃ of FIG. 11 is one example of a signal-transfer sequence concerning apaging operation, which is an alteration operation. This signal-transfersequence may be applied to signal-transfer sequences for alterationoperations such as a size-magnification operation, a size-reductionoperation, and a scrolling operation. Processes in S₅₃ are approximatelyidentical to those in S₅₂ except for the performance of the alterationoperation affecting an identified page in S₅₃ instead of the performanceof the deletion operation in S₅₂.

S₆₁ of FIG. 15 is an example of a signal transfer sequence in whichaddition operations are specified by the operators on the respectiveterminals. This sequence is only a sequence for a case where S₅₀ and S₅₁of FIG. 11 are simultaneously carried out and a particular descriptionfor the sequence of S₆₁ is therefore omitted.

S₆₂ is an example of a signal transfer sequence in which an additionoperation and a deletion operation are specified by the operators on theterminals, respectively. This sequence is a sequence for a case whereS₅₀ and S₅₂ of FIG. 11 are simultaneously carried out and will now bedescribed with reference to FIG. 12. First, the terminal A, on which adeletion operation C is specified by the operator, determines in S₈₀that a tele-writing operation exists. Because the relevant tele-writingoperation comprises the deletion operation, the terminal Acorrespondingly edits transmission data in S₈₈ and then sends the editeddata to the remote terminal B via the line control unit in S₈₉.Subsequently, the terminal A carries out S₈₀ and S₈₁ thus determiningthat an addition operation-D specified by the operator on the terminal Bexists, and executing the subsequent step corresponding to the resultYES of S₈₁.

Subsequently, the terminal A accepts the data sent from the terminal Bin S₈₂, then determines a drawing area using document identifier andpage number indicated by the accepted data in S₈₃, and determines inS₈₄, using the terminal number indicated by the accepted data, whetheror not the command indicated by the accepted data comprises a returningcommand of a go-and-return type command. In this case, because therelevant command corresponds to the addition operation and thuscomprises a one-way command, the terminal A executes the subsequent stepcorresponding to the result NO of S₈₄. Then, in S₈₅, an affecting taskis to be determined in accordance with the determination table shown inFIG. 13. In this case, the terminal A now acting as the local-terminalis in the deletion operation and the data received from the terminal Bnow acting as a remote terminal comprises an addition-operationaffecting command. As a result, TASK-1 is selected. Subsequently, theterminal A branches off into the selected TASK-1 in S₈₆ and executesTASK-1 accordingly in S₈₇. In the processes of TASK-1 as shown in FIG.14A, the terminal A draws a specified element in the determined drawingarea in accordance with the received addition-operation affectingcommand in S₉₃.

Processes in the terminal B will now be described. The terminal B,having an additional operation D specified by the operator on it, thusdetermines in S₈₀ that tele-writing operation exists. Because therelevant tele-writing operation comprises the addition operation, inS₈₆, the terminal B draws the appropriate object in the relevant drawingarea and correspondingly edits transmission information. Then, theterminal B sends the edited data to the terminal A in S₈₉. Then, theterminal B executes S₈₀ and S₈₁ so as to determine that the receiveddata, indicating the deletion operation C, sent from the terminal A,exists. Thus, the terminal B executes the subsequent step correspondingto the result YES of S₈₁. Then, the terminal B accepts the data sentfrom the terminal A in S₈₂ and determines the relevant drawing areausing document identifier and page number indicated by the accepted datain S₈₃. Then, the terminal B determines using the terminal numberindicated by the accepted data, in S₈₄, whether or not the commandindicated by the accepted data is the returning command of thego-and-return type command. In this case, because the deletion-operationaffecting command comprises the going command of the go-and-return typecommand, the terminal B executes the subsequent step corresponding tothe result NO of S₈₄. In S₈₅, the terminal B determines an affectingtask in accordance with the table shown in FIG. 13. In this case, theterminal B now acting as a local-terminal is in the addition operationand the data received from the terminal A now acting as a remoteterminal comprises a deletion-operation affecting command. As a result,TASK-2 is selected.

Subsequently, the terminal B branches off into the selected TASK-2 inS₈₆ and executes TASK-2 accordingly in S₈₇. In the processes of TASK-2as shown in FIG. 14B, the terminal B removes a specified element fromthe determined drawing area in accordance with the receiveddeletion-operation affecting command in S₉₄. Then, because thedeletion-operation affecting command comprises the go-and-return typecommand, the terminal B sends back the received data as it is to theremote terminal A in S₉₅. Then the terminal A, after receiving the datathus sent back from the terminal B, executes S₈₀, S₈₁ and S₈₂respectively so as to accept the thus sent-back data. Then, the terminalA determines in S₈₃ the relevant drawing area using the documentidentifier and page number indicated by the thus accepted data. Then,the terminal A determines in S₈₄ that the command indicated by theaccepted data comprises the returning information. As a result, theterminal A executes the corresponding deletion affecting the determineddrawing area in S₉₀. Thus, S₆₂ of FIG. 15 has been described.

The reason that the terminal does not execute the relevant deletionaction immediately after the corresponding deletion operation isspecified by the operator on the terminal but rather performs the actionwhen the terminal receives the corresponding returning command, will nowbe described. Such a procedure is applied to the case of S₆₂ where anaddition operation and a deletion operation are simultaneously specifiedby the operators on the respective terminals. If both adeletion-operation affecting command and an addition-operation affectingcommand are similar one-way commands and processes associated with thesecommands are also similar, a phenomenon shown in FIG. 10 will occur.That is, first the deletion action is performed and then the additionaction is performed in the terminal A. On the other hand, first theaddition action is performed and then the deletion action is performedin the terminal B. If such actions are performed on the mutuallyduplicated drawing areas of the respective terminals, the result isdifferent in the drawing areas of the respective terminals. In order toprevent such a difference from occurring, the deletion command is madeto be of the command type go-and-return. The deletion is not performedwhen the deletion operation is specified by the operator but thecorresponding affecting information is sent to the remote terminal.Then, the deletion action is performed when the corresponding returningcommand is received. As a result, each picture of the respective drawingareas is changed as shown in FIG. 16, no difference existing between thefinal pictures each located at the bottom of FIG. 16. The abovedescribed operations concerning the deletion-operation affecting commandcorrespond to the series of changed pictures shown in FIG. 16.

However, there arises another problem as follows: Since the deletionaction is performed after receiving of the corresponding returningcommand, a certain time lag is created between the start ofspecification of the relevant operation by the operator and therealization of the corresponding effect. Such a time lag may degrade theoperation performance. In order to eliminate such a problem, thetele-writing terminal device in the second embodiment of thetele-writing system according to the present invention may be made sothat the resulting picture changing process is one as shown in FIG. 17.In this case, with a view point to better operation performance, thedeletion action is performed immediately after the correspondingdeletion operation is specified by the operator. Then, in order toeliminate the difference between documents, the same deletion action isagain performed when the corresponding returning command is received. Inthis case, even though the same deletion action is performed twice, boththe requirements, better operation performance and document-differenceelimination, can be fulfilled. Actually, the description of thetele-writing terminal device in the second embodiment is generally basedon the operation procedure resulting in the picture changing as shown inFIG. 16, in order to simplify the description. The above-described basicscheme concerning the deletion-operation affecting command is similar tothat concerning the alteration-operation affecting command. Therefore,the alteration-operation affecting command is also of the go-and-returntype. However, there are schemes that are specific to thealteration-operation affecting command. These specific schemes will bedescribed below in the description of the tele-writing terminal devicein the second embodiment.

S₆₃ of FIG. 15 is an example of a signal transfer sequence in which anaddition operation and a paging operation are specified by the operatorson the terminals, respectively. This sequence is a sequence for a casewhere S₅₀ and S₅₃ of FIG. 11 are simultaneously carried out and will nowbe described with reference to FIG. 12. First, the terminal A, on whicha paging operation E is specified by the operator, determines in S₈₀that a tele-writing operation exists. Because the relevant tele-writingoperation comprises the paging operation, the terminal A correspondinglyedits transmission data in S₈₈ and then sends the edited data to theremote terminal B via the line control unit in S₈₉.

Subsequently, the terminal A carries out S₈₀ and S₈₁ thus determiningthat an addition operation D specified by the operator on the terminal Bexists, thus executing the subsequent step corresponding to the resultYES of S₈₁. Subsequently, the terminal A accepts the data sent from theterminal B in S₈₂, then determines a drawing area using documentidentifier and page number indicated by the accepted data in S₈₃, anddetermines in S₈₄, using the terminal number indicated by the accepteddata, whether or not a command indicated by the accepted data comprisesa returning command of a go-and-return type command. In this case,because the relevant command corresponds to the addition operation andthus comprises a one-way command, the terminal A executes the subsequentstep corresponding to the result NO of S₈₄. Then, in S₈₅, an affectingtask is determined in accordance with the determination table shown inFIG. 13. In this case, the terminal A now acting as the local-terminalis in the alteration operation (paging operation) and the data receivedfrom the terminal B now acting as a remote terminal comprises anaddition-operation affecting command. As a result, TASK-1 is selected.Subsequently, the terminal A branches off into the selected TASK-1 inS₈₆ and executes TASK-1 accordingly in S₈₇. In the processes of TASK-1as shown in FIG. 14A, the terminal A draws a specified element on thedetermined drawing area in accordance with the receivedaddition-operation affecting command in S₉₃.

Processes in the terminal B will now be described. The terminal B,having an addition operation D specified by the operator, thusdetermines in S₈₀ that a tele-writing operation exists. Because therelevant tele-writing operation comprises the addition operation, inS₈₆, the terminal B draws the appropriate element in the relevantdrawing area and correspondingly edits transmission information. Then,the terminal B sends the edited data to the terminal A in S₈₉.

Then, the terminal B executes S₈₀ and S₈₁ thus determining that thereceived data, indicating the paging operation-E, sent from the terminalA, exists. Then, the terminal B executes the subsequent stepcorresponding to the result YES of S₈₁. Then, the terminal B accepts thedata sent from the terminal A in S₈₂ and determines the relevant drawingarea using the document identifier and page number indicated by theaccepted data in S₈₃. Then, the terminal B determines using the terminalnumber indicated by the accepted data, in S₈₄, whether or not thecommand indicated by the accepted data is the returning command of thego-and-return type command. In this case, because the paging-operationaffecting command comprises the going command of the go-and-return typecommand, the terminal B executes the subsequent step corresponding tothe result NO of S₈₄. In S₈₅, the terminal B determines an affectingtask in accordance with the table shown in FIG. 13. In this case, theterminal B now acting as the local-terminal is in the addition operationand the data received from the terminal A now acting as a remoteterminal comprises an alteration-operation (paging-operation) affectingcommand. As a result, TASK-4 is selected.

Subsequently, the terminal B branches off into the selected TASK-4 inS₈₆ and executes TASK-4 accordingly in S₈₇. In the processes of TASK-4as shown in FIG. 18A, first the terminal B disables input of furtheraddition operations (that is, any attempt to specify another operationis ignored, for example) by the operator and sends, to the remoteterminal A, data associated with an addition executed due to analready-specified addition operation by the operator, if it exists, inS₉₈. This halting is carried out so as to make coincident areas on thecommon pictures which the relevant tele-writing operations affect. Then,the terminal B alters a certain object on the relevant drawing area inaccordance with the received paging-operation affecting command in S₉₉.Then, because the paging-operation affecting command is analteration-operation affecting type command, the terminal B sends backthe received data, as it is, as the returning command, to the remoteterminal A in S₁₀₀.

Terminal A, after receiving the data thus sent back from the terminal B,executes S₈₀, S₈₁ and S₈₂ respectively so as to accept the thussent-back data. Then, the terminal A determines in S₈₃ the relevantdrawing area using the document identifier and page number indicated bythe accepted data. Then, the terminal A determines in S₈₄ that thecommand indicated by the accepted data comprises the returninginformation of the paging information. As a result, the terminal Acorrespondingly alters the object in the relevant drawing area and thendisplays the drawing area, on the common picture, resulting from thealteration in S₉₀. Thus, S₆₃ of FIG. 15 has been described.

S₆₄ of FIG. 11 is one example of a signal-transfer sequence whereindeletion operations are simultaneously specified by the operators onboth the terminals respectively. This signal-transfer sequence is only asequence for a case where steps each corresponding to S₅₂ of FIG. 11 aresimultaneously carried out and a particular description for the sequenceof S₆₄ will be omitted accordingly.

S₆₅ is an example of a signal transfer sequence in which alterationoperations are simultaneously specified by the operators on theterminals, respectively. This sequence is a sequence for a case wheresteps each corresponding to S₅₃ of FIG. 11 are simultaneously carriedout and will now be described with reference to FIG. 12. First, theterminal A, on which a paging operation G is specified by the operator,thus determines in S₈₀ that a tele-writing operation exists. Because therelevant tele-writing operation comprises the paging operation, theterminal A correspondingly edits transmission data in S₈₈ and then sendsthe edited data to the remote terminal B via the line control unit inS₈₉.

Subsequently, the terminal A carries out S₈₀ and S₈₁ thus determinesthat a paging operation G specified on the terminal B by the operatorexists, and executing the subsequent step corresponding to the resultYES of S₈₁. Subsequently, the terminal A accepts the data sent from theterminal B in S₈₂, then determines a drawing area using the documentidentifier and page number indicated by the accepted data in S₈₃, anddetermines in S₈₄, using the terminal number indicated by the accepteddata, whether or not the command indicated by the accepted datacomprises a returning command of a go-and-return type command. In thiscase, because the relevant command corresponds to the paging operationand thus comprises the going command of the go-and-return type command,the terminal A executes the subsequent step corresponding to the resultNO of S₈₄. Then, in S₈₅, an affecting task is determined in accordancewith the determination table shown in FIG. 13. In this case, theterminal A now acting as the local-terminal is in the alteration(paging) operation and the data received from the terminal B now actingas a remote terminal comprises an alteration (paging)-operationaffecting command. As a result, TASK-6 is selected. Subsequently, theterminal A branches off into the selected TASK-6 in S₈₆ and executesTASK-6 accordingly in S₈₇. In the processes of TASK-6 as shown in FIG.19, the terminal A disable input of further alteration operations by theoperator in S₁₀₃. Then, the terminal A edits the receivedpaging-operation affecting command as being an invalid command and thensends back the edited command as the returning command of thego-and-return type command in S₁₀₄.

Processes in the terminal B will now be described and are similar tothose in the terminal A described above. That is, the terminal Bdisables the input of further paging operations H by the operator; andsends back the paging-operation-H affecting command as an invalidcommand. On the other hand, the terminal A repeats S₈₀ and S₈₁ so as towait for a command to be sent back from the remote terminal B. Then,after receiving the sent-back data, the terminal A examines the receiveddata through S₈₂ and S₈₃. Because it is found that the relevant commandcomprises the returning command of the go-and-return type command as aresult of the examination, the terminal A executes the subsequent stepcorresponding to the result YES of S₈₄. Thus, the terminal A executesS₉₀. However, in S₉₀, since the received paging-operation affectingcommand comprises invalid data, the terminal A executes nothingregarding the relevant command. The sequence performed by the terminal Bis the same as that performed by the terminal A described above.

The above description is that for the case where paging operations aresimultaneously specified by the operators on the terminals,respectively. In such a case, as described above, as a result, thespecifications of the paging operations by the operators are canceled.There may be another arrangement of the tele-writing terminal device inthe second embodiment, as follows: Priority is given to either one ofthe terminals; then the paging operation specified by the operator onthe terminal having the priority takes effect so that the correspondingpaging is realized; and the specification of the paging operationspecified on the other terminal by the operator is canceled. Both thearrangement resulting in canceling both the specifications by theoperators and the arrangement resulting in activating one and cancelingone have the following common concept: If duplicate paging operationsare specified, simultaneous paging execution is prevented. such aconcept is necessary because simultaneous occurrence of differentactions resulting from the paging results in the following phenomenon:The fifth page is displayed in the picture of a first terminal while thethird page is displayed in the picture of a second terminal, forexample. Thus, coincidence in displayed contents between both terminalscan not be ensured. The tele-writing terminal device in the firstembodiment of the tele-writing system according to the present inventionallows such non-coincidence of displayed contents and normaltele-writing execution is ensured there. On the other hand, in thetele-writing terminal device in the second embodiment of thetele-writing system according to the present invention, such coincidencein displayed contents is mandatory so that storage means is eliminated.The coincidence in displayed contents may be ensured by preventingsimultaneous different paging executions from being made.

S₇₁ is an example of a signal transfer sequence in which a deletionoperation and a paging operation are simultaneously specified on theterminals by the operators, respectively. This sequence is a sequencefor a case where S₅₂ and S₅₃ of FIG. 11 are simultaneously carried outand will now be described with reference to FIG. 12. First, the terminalA, on which a deletion operation G is specified by the operator, thusdetermines in S₈₀ that a tele-writing operation exists. Because therelevant tele-writing operation comprises the deletion operation, theterminal A correspondingly edits transmission data in S₈₈ and then sendsthe edited data to the remote terminal B via the line control unit inS₈₉. Subsequently, the terminal A carries out S₈₀ and S₈₁, thusdetermining that the paging operation H specified on the terminal B bythe operator exists, thus executing the subsequent step corresponding tothe result YES of S₈₁. Subsequently, the terminal A accepts the datasent from the terminal B in S₈₂, then determines a drawing area usingthe document identifier and page number indicated by the accepted datain S₈₃, and determines in S₈₄, using the terminal number indicated bythe accepted data, whether or not the command indicated by the accepteddata comprises a returning command of a go-and-return type command. Inthis case, because the relevant command corresponds to the pagingoperation and thus comprises the going command of the go-and-return typecommand, the terminal A executes the subsequent step corresponding tothe result NO of S₈₄. Then, in S₈₅, an affecting task is determined inaccordance with the determination table shown in FIG. 13. In this case,the terminal A now acting as the local-terminal is in the deletionoperation and the data received from the terminal B now acting as aremote terminal comprises an alteration-operation affecting command(paging). As a result, TASK-5 is selected. Subsequently, the terminal Abranches off into the selected TASK-5 in S₈₆ and executes TASK-5accordingly in S₈₇. In the processes of TASK-5 as shown in FIG. 18B, theterminal A disables the input of further deletion operation by theoperator, and sends data associated with a deletion executed due to analready-specified deletion operation by the operator if it exists, inS₁₀₁. The terminal A does not immediately execute the receivedpaging-operation affecting command and registers the command as anaffecting-waiting command in S₁₀₂. Then, the terminal A waits for thedeletion-operation affecting command, sent previously as mentionedabove, to be sent back. Then, the terminal A executes the sent backdeletion-operation affecting command so that the actual deletion of arelevant object from the relevant picture is performed in₉₀ as describedbelow, after receiving the sent back deletion-operation affectingcommand. Then, after the actual deletion, the terminal A executes theabove mentioned received paging-operation affecting command so that theactual paging of the relevant document is performed in S₉₂ describedbelow.

Processes in the terminal B will now be described. The terminal B,having the paging operation I specified by the operator, as a resultdetermines in S₈₀ that a tele-writing operation exists. Because therelevant existing tele-writing operation comprises the paging operation,the terminal B correspondingly edits transmission data in S₈₈. Then, theterminal B sends the edited data to the remote terminal A in S₈₉. Then,the terminal B executes S₈₀ and S₈₁, thus determining the existence ofthe received data concerning the deletion operation G sent from theterminal A. Thus, the terminal B executes the subsequent stepcorresponding to the result YES of S₈₁. Subsequently, the terminal Baccepts the data sent from the terminal A in S₈₂, then determines adrawing area using a document identifier and page number indicated bythe accepted data in S₈₃, and determines in S₈₄, using the terminalnumber indicated by the accepted data, whether or not a commandindicated by the accepted data comprises a returning command of ago-and-return type command. In this case, because the relevant commandcorresponds to the deletion operation and thus comprises the goingcommand of the go-and-return type command, the terminal A executes thesubsequent step corresponding to the result NO of S₈₄. Then, in S₈₅, anaffecting task is determined in accordance with the determination tableshown in FIG. 13. In this case, the terminal B now acting as thelocal-terminal is in the alteration (paging) operation and the datareceived from the terminal A now acting as a remote terminal comprises adeletion-operation affecting command. As a result, TASK-2 is selected.Subsequently, the terminal A branches off into the selected TASK-2 inS₈₆ and executes TASK-2 accordingly in S₈₇. The processes of TASK-2 havebeen already described above and the duplicating descriptions istherefore omitted.

The terminal A, after receiving the data sent back from the terminal B,executes S₈₀, S₈₁ and S₈₂ respectively so as to accepts the thussent-back data. Then, the terminal A determines in S₈₃ the relevantdrawing area using the document identifier and page number indicated bythe thus accepted data. Then, the terminal A determines in S₈₄ that thecommand indicated by the accepted data comprises the returninginformation of the deletion information. As a result, the terminal Acorrespondingly removes a specified element from the relevant drawingarea in S₉₀. Then, since the terminal A has the registeredaffecting-waiting command, the result of the determination in S₉₁becomes YES. As a result, the terminal A executes the registeredaffecting-waiting paging-operation affecting command so that the actualpaging of the relevant document is performed. Then, the terminal A sendsback the relevant paging-operation-H affecting command to the remoteterminal B in S₉₂. On the other hand, the terminal B, the receiving thepaging-operation-H affecting command sent form the terminal A, executesthe paging-operation-H affecting command so that the actual paging ofthe relevant document is performed.

Further, the present invention is not limited to the above describedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

What is claimed is:
 1. A tele-writing system comprising:page anddocument identifier-adding means for adding a page identifier and adocument identifier to tele-writing information sent from a firsttele-writing system to a second tele-writing system viatelecommunication, said page and document identifiers being used toidentify 1) a page of a multi-page document on said first tele-writingsystem processed and 2) a corresponding page of a correspondingmulti-page document to be processed as a result of a first tele-writingoperation being specified, means, on said second tele-writing system,for executing said first tele-writing operation on a second picturedisplayed on said second tele-writing system according to saidtele-writing information which comprises coordinate information andwhich modified a first picture on said first tele-writing system, saidmeans for executing including page and document identifying means foridentifying, using said page and document identifiers added to saidtele-writing information received from said first tele-writing system,the corresponding page of the corresponding multi-page document to beprocessed as a result of said first tele-writing operation; means foradding a sequential number to said tele-writing information to determinewhether the page of the multi-page document and the corresponding pageof the corresponding multi-page document have equivalent contents; andmeans for re-executing a second tele-writing operation previouslyexecuted on said second tele-writing system when, based on saidsequential number, it is determined that 1) a change in an order ofoperation of said first and second tele-writing operations produces saidfirst and second pictures which are different and 2) said first andsecond tele-writing operations have been performed at the firsttele-writing system in a different order than at said secondtele-writing system.
 2. The tele-writing system according to claim 1,further comprising:terminal-number adding means for adding a terminalnumber to said sending tele-writing information, said terminal numberconcerning said tele-writing system; and terminal identifying means foridentifying, using a terminal number added to said received tele-writinginformation, said second tele-writing system.
 3. The tele-writing systemaccording to claim 2, wherein said terminal number is to be given to aparticular tele-writing system such as said tele-writing system.
 4. Thetele-writing system according to claim 1, further comprising:means forspecifying a drawing area to be updated based on said tele-writinginformation; means for updating a common picture displayed on a commonscreen when the drawing area to be updated is being displayed on thecommon screen; and means for updating information stored in a storageunit when the drawing area to be updated is not being displayed on saidcommon screen.
 5. A tele-writing system comprising:page and documentidentifier-adding means for adding a page identifier and a documentidentifier to tele-writing information sent from a first tele-writingsystem to a second tele-writing system via telecommunication, said pageand document identifiers being used to identify 1) a page of amulti-page document on said first tele-writing system processed and 2) acorresponding page of a corresponding multi-page document to beprocessed, as a result of a first tele-writing operation beingspecified, means, on said second tele-writing system, for executing saidfirst tele-writing operation on a second picture displayed on saidsecond tele-writing system according to said tele-writing informationwhich modified a first picture displayed on said first tele-writingsystem, said means for executing including page and document identifyingmeans for identifying, using said page and document identifiers added tosaid tele-writing information received from said first tele-writingsystem, the corresponding page of the corresponding multi-page documentto be processed as a result of said first tele-writing operation; meansfor adding a sequential number to said tele-writing information todetermine whether the page of the multi-page document and thecorresponding page of the corresponding multi-page document haveequivalent contents; and means for re-executing a second tele-writingoperation previously executed on said second tele-writing system when,based on said sequential number, it is determined that 1) a change in anorder of operation of said first and second tele-writing operationsproduces first and second pictures which are different and 2) said firstand second tele-writing operations have been performed at the firsttele-writing system in a different order than at said secondtele-writing system; means for specifying a drawing area to be updatedbased on said tele-writing information; means for updating a commonpicture displayed on a common screen when the drawing area to be updatedis being displayed on the common screen; and means for updatinginformation stored in a storage unit when the drawing area to be updatedis not being displayed on said common screen.
 6. A tele-writing systemcomprising:a first tele-writing system; and a second tele-writingsystem, wherein the first tele-writing system comprises:firstidentifier-adding means for adding a page identifier and a documentidentifier to first tele-writing information sent from the firsttele-writing system to the second tele-writing system viatelecommunication, the first tele-writing information including a firsttele-writing operation to be performed based on a first localmodification, the page and document identifiers identifying a first pageof a first copy of a multi-page document to be processed based on thefirst tele-writing operation, and means for adding a firstlocally-specified sequential number to the first tele-writinginformation; wherein the second tele-writing system comprises: secondidentifier-adding means for adding the page and document identifiers tosecond tele-writing information sent from the second tele-writing systemto the first tele-writing system via telecommunication, the secondtele-writing information including a second tele-writing operation to beperformed, the page and document identifiers identifying the first pageof a second copy of the multi-page document to be processed by the firstand second tele-writing operations, and means for adding a secondlocally-specified sequential number to the second tele-writinginformation; wherein the first and second tele-writing systems eachfurther comprise:means for executing the first and second tele-writingoperations on respective first and second pictures displayed on thefirst and second tele-writing systems, respectively, means for using thefirst and second locally-specified sequential numbers to determinewhether the first and second pictures are equivalent after therespective means for executing execute the first and second tele-writingoperations, and means for re-executing at least one of the first andsecond tele-writing operations on a corresponding one of the first andsecond tele-writing systems to produce first and second pictures whichare equivalent, the means for re-executing including means forre-executing the at least one of the first and second tele-writingoperations when a change in an order of operation of the first andsecond tele-writing operations produces first and second pictures whichare different and when the first and second tele-writing operations havebeen performed at the first tele-writing system in a different orderthan the first and second tele-writing operations were performed at thesecond tele-writing system.